(1) Field of the Invention
The present invention relates to an artificial skin to be transplanted on a wound skin surface such as a burned or scratched skin surface, and a method of producing the same.
(2) Brief Description of the Prior Art
Conventionally, artificial skins made of collagen and so on for a temporary wound-covering material are used in practice. On the other hand, cell-incorporating artificial skins having biocompatibility are proposed by E. Bell (Science 211, 1052 (1981)) and I. V. Yannas et al. (Science 215, 174 (1982)). However, it takes a long cell culture period (about one month) in order to obtain an artificial skin by Bell et al., and the size of an avilable artificial skin piece is limited since agarlike collagen serving as the cell carrier is soft. Because of these drawbacks, the artificial skins by Bell et al. are not to this day applied for clinical use.
Currently, a method for fast culturing cells is proposed by Gallico G. G. et al. (NEJM 311, 448-451 (1984)). According to this method, epidermal cells isolated from a skin piece are cultured using 3T3 (an established cell strain obtained from a swiss mouse subcutaneous tissue) as supporting cells, and the cultured epidermal sheet is treated by dispase and removed from the supporting cells. The sheet is applied on an ointment-coated gauze to be used for transplantation.
In this case, although the cell culture period is shortened, the supporting cells remaining in the epidermal sheet adversely affect the recipient's body. This method also has the following defects:
(1) The epidermal sheet must be removed by dispase treatment.
(2) The area of the epidermal sheet is reduced to about 1/4 the original area upon removing, thus causing loss in the epidermal sheet.
(3) A carrier, such as a gauze, for the epidermal sheet is additionally required.
(4) Since only the epidermal sheet is transplanted without a dermis component, no scarring remains after healing. In the case of a critical disorder such as a deficiency in the dermis deep portion, a sufficient effect cannot be expected by this method.